The background description provided here is for the purpose of generally presenting the context of the disclosure. Work of the presently named inventors, to the extent it is described in this background section, as well as aspects of the description that may not otherwise qualify as prior art at the time of filing, are neither expressly nor impliedly admitted as prior art against the present disclosure.
To reduce the quantity of undesirable particulate matter and nitrogen oxide (NOx) emitted to the atmosphere during internal combustion engine operation, a number of exhaust aftertreatment systems have been developed. A need for exhaust aftertreatment systems particularly may arise when diesel combustion processes are implemented.
One method used to reduce NOx emissions from internal combustion engines is known as selective catalytic reduction (SCR). SCR may include injecting a reagent into the exhaust stream of the engine to form a reagent and exhaust gas mixture that is subsequently passed through a reactor containing a catalyst. The catalyst is capable of reducing the NOx concentration in the presence of the reagent. For example only, the catalyst may include activated carbon or metals, such as platinum, vanadium, or tungsten. An aqueous urea solution is known to be an effective reagent in SCR systems for diesel engines.
Various pressure sensors are implemented in exhaust aftertreatment systems. Examples of pressure sensors include exhaust pressure sensors, reagent pressure sensors, and other types of pressure sensors. Pressure sensors are connected to a controller that is separate from the pressure sensors via respective sets of wires. Each pressure sensor includes a sensing element that generates an analog signal corresponding to a sensed pressure. The pressure sensors output their analog signals to the controller via the respective sets of wires. Pressure sensors may also include additional signal conditioning circuitry that conditions the analog signals before the analog signals are output. The controller generates digital values based on the analog signals.
This pressure sensing system, however, is costly. A need exists to provide a lower cost solution for measuring and responding to pressures.